Preparation of white oils with organo-
aluminum activated iron group metal
catalysts

ABSTRACT

A PROCESS FOR UPGRADING AND IMPRIVING THE COLOR, ODOR AND STABILITY OF PETROLEUM OILS TO RENDER THE LATER SUITABLE FOR USE IN SPECIALTY APPLICATIONS. RAW DISTILLATES AND SEMIREFINED OILS OF SUITABLE BOILING RANGE AND VISCOSITY ARE REFINED, OR FURTHER REFINED, IN A HYDROGENATIO PROCESS, AT SUITABLE CONDITIONS, IN THE PRESENCE OF A CATALYST WHICH COMPRISES A SUPPORT AND A TRANSITION METAL COMPLEXED WITH AN ORGANOMETALLIC COMPOUND, TO YIELD COLORLESS MINERAL OILS, I.E., WHITE OILS. THESE HIGHLY REFINED OILS ARE USED IN PHARMACEUTICALS AND COSMETICS AND SIMILAR COMPOSITIONS REQUIRING OIL COMPONENTS THAT MEET CERTAIN HIGH QUALITY STANDARDS.

United States Patent PREPARATION OF WHITE OILS WITH ORGANO- ALUMINUMACTIVATED IRON GROUP METAL CATALYSTS John B. Gilbert and RobertKartzmark, Sarnia, Ontario, Canada, assignors to Esso Research andEngineering Company No Drawing. Original No. 3,658,692, dated Apr. 25,1972, Ser. No. 871,943, Oct. 28, 1969. Application for reissue Sept. 18,1972, Ser. No. 290,063

Int. Cl. Cg 23/02 US. Cl. 208-439 35 Claims Matter enclosed in heavybrackets appears in the original patent but forms no part of thisreissue specification; matter printed in italics indicates the additionsmade by reissue.

ABSTRACT OF THE DISCLOSURE A process for upgrading and improving thecolor, odor and stability of petroleum oils to render the lattersuitable for use in specialty applications. Raw distillates andsemirefined oils of suitable boiling range and viscosity are refined, orfurther refined, in a hydrogenation process, at suitable conditions, inthe presence of a catalyst which comprises a support and a transitionmetal complexed with an organometallic compound, to yield colorlessmineral oils, i.e., White oils. These highly refined oils are used inpharmaceuticals and cosmetics and similar compositions requiring oilcomponents that meet certain high quality standards.

White oils are highly refined oils derived from petroleum which havebeen extensively treated to virtually eliminate oxygen, nitrogen, sulfurcompounds and reactive hydrocarbons such as aromatic hydrocarbons. Whiteoils fall into two classes, i.e., technical white oils which are used incosmetics, textile lubrication, insecticide base oils, etc., and theeven more highly refined pharmaceutical White oils which are used indrug compositions, foods and for the lubrication of food handlingmachinery. For all of these applications white oils must be chemicallyinert and without color, odor and taste.

The conventional method of making white oils involves refining petroleumoils with sulfuric acid. The acid removes impurities and reactivecompounds by chemical reaction and by solvation. Acid treating is costlybecause it results in low product yields and produces large amounts ofsludge and spent acid which must be disposed of, along with spent clayused for treatment of the product to remove traces of sulfonates and thelike.

It is known to produce semi-refined oils by extraction methods, withsubsequent hydrogenation of the raffinates, though the high qualitystandards required of white oils cannot be met by such techniques. It isthus known that selected oils can be extracted with solvents to obtain arafiinate low in aromatics, and that the raffinate can be subjected tohydrogenation in the presence of an active hydrodesulfurization catalystto saturate or destroy heterocyclic compounds containing sulfur,nitrogen and oxygen to produce a semi-refined oil, or oil whichapproaches but does not meet white oil specifications. White oilspecifications are rather diflicult to meet, for such oils must have acolor of +30 Saybolt, must pass the UV Absorption Test (ASTM D-2008) andthe USP Hot Acid Test (ASTM D-565).

Nonetheless, it is a primary objective of the present invention toobviate these and other prior art difficulties and, in particular, toprovide a new and improved process, or process combination, formanufacture of White oils which will eliminate any necessity of acidtreating.

A further object is to provide a process for manufacturing highly stablewhite oils from raw distillates and ice semi-refined oils in good yieldcontaining very insignificant concentrations, it any, of sulfur,nitrogen, oxygen and aromatics.

A specific object is to provide a process combination including asequence of steps for manufacturing semi-refined oils, and subsequenttreatment of such oils in the presence of highly active complexcatalysts, at suitable conditions, for essentially complete saturationof the aromatics to produce white oils in good yield.

These and other objects are achieved in accordance with the presentinvention which provides a process comprising treating petroleum oils ofsuitable boiling range and viscosity, including raw distillates andsemi-refined oils, and refining the latter to white oil specificationsby hydrogenation with highly active supported transition metal complexcatalysts, at hydrogenation conditions. The catalyst complex is formedby depositing a transition metal salt from solution on a suitablesupport material and activating the salt with a liquid-solubleorgano-metallic compound.

Raw distillates and semi-refined oils of suitable boiling range andviscosity, provide feedstocks suitable for use in the preparation ofwhite oils by contact with the highly active complex catalyst, athydrogenation conditions. The feedstocks can be obtained by conventionalprocessing comprising (a) solvent extracting a lubricating oil or rawdistillate to obtain a raftinate; (b) treating the rafilnate withhydrogen over an active hydrodesulfurization catalyst at conditionssuitable to reduce the sulfur content, and then (0) distilling thehydrotreated product under vacuum to remove overhead a low boilingfraction, while recovering a higher boiling, semi-refined low sulfur oilfraction. Suitably, e.g., a petroleum oil, obtained by distillation,boiling in the range of 400 to 1,0-25 F. and having a viscosity of about35 to 2,500 SSU at 100 F. can be extracted with a suitable solvent foraromatic hydrocarbons, e.g., phenol, furfural or S0 to produce arafiinate boiling in the range of about 400 to 1,025 F. The rafiinatecan be hydrogenated, if desired, or necessary, with a conventionalhydrodesulfurization catalyst to produce a low sulfur oil containing,preferably, less than about 5 p.p.m. sulfur. This oil, or feedstock, canthen be upgraded to specification white oil by a second hydrogenation inthe presence of a highly active catalyst complex formed by a supportedtransition metal salt, activated with a liquid-soluble organo-metalliccompound.

Suitable feedstocks for conversion to white oils over the highly activecomplex catalysts are those boiling within a range of from about 400 to1,025 F., and higher, preferably from about 650 F. to 1,025 F. Whilehigher boiling feedstocks can be used, this is not generally desirableinasmuch as process conditions must be increased in severity to animpractical extent. Viscosities range preferably from about 30 to about2,500 SSU at 100 F., and more preferably from about 35 to 500 SSU at 100F., but viscosity can be readily controlled, e.g., by topping. Thearomatics content of the initially treated feed is not critical inasmuchas aromatics can be reduced to an acceptable level by extraction andprehydrogenation, but the aromatics content of the feedstock directlyused for treatment and hydrogenation with the complex catalyst shouldpreferably be no greater than about 5 percent, based on the weight ofthe feedstock, and is more preferably less.

Conventional solvent extraction processes can be used to reduce thearomatic hydrocarbon content of the oil. For example, a preferredextraction with phenol at a temperature in the range of 100 to 300 F.and a pressure in the range of about ambient to 100 p.s.i.g. provides asuitable means of aromatics removal. Suitably, from about to 500 percentof the solvent, based on the weight of the oil, is employed in theextraction.

The rafiinate is hydrogenated at relatively severe conditions to removethe heterocyclic compounds, and in particular to reduce the sulfurcontent of the oil, preferably to less than about 5 ppm. sulfur.Suitable hydrogenation conditions include temperatures in the range ofabout 400 to 800 F., and preferably in the range of about 600 to 700 F.;pressures in the range of about 1,000 to 10,000 and preferably in therange of about 500 to 5,000 p.s.i.g.; space velocities in the range ofabout 0.1 to v./hr./v., preferably in the range of about 0.1 to 2v./hr./v.; and hydrogen rates of from about 500 to 10,000 s.c.f./bbl.and preferably hydrogen rates of about 1,000 to 5,000 s.c.f./ bbl. offeed. Suitable hydrotreating catalysts comprise one or morehydrogenation metals supported on a suitable carrier material. Themetals are in the form of metal oxides or metal sulfides. Salts of GroupVI and Group VIII metals are the preferred hydrogenating components.Specifically, oxides or sulfides of molybdenum, tungsten, cobalt, nickeland iron are used. Alumina, alumina containing 1 to 10 weight percentsilica, bauxite, kieselguhr, etc., are preferred support materials. Themost preferred catalysts are sulfided cobalt molybdate or sulfidednickel m0- lybdate on alumina or silica alumina. The catalyst can bedisposed for contacting in a fixed bed for liquid phase or mixed phasecontacting. This first stage of hydrogenation performs severalfunctions, including hydrodesulfurization, hydrodenitrogenation,saturation of olefins, some saturation of aromatic hydrocarbon rings,etc. The hydrorefined, or semi-refined, oils can be topped, if desired,to adjust viscosity and specific gravity in accordance with marketrequirements.

The feedstocks, or white oil base stocks, can be hydrogenated in thepresence of the high activity complex catalysts to produce white oils.Pressures, space velocities and hydrogen rates are essentially the sameas in the first hydrogenation stage wherein salts of Groups VIB and VIIIhydrogenation metals are employed, though temperatures are generallylower. Preferably, the temperature employed in hydrogenation of thefeedstocks with the highly active complex catalysts ranges from about350 to 600 F., and more preferably from about 475 to 525 F. The highlyactive complex catalysts are prepared by the steps of impregnating asupport with a solution of a liquid soluble compound of a transitionmetal, preferably a Group VIII metal of the Periodic Chart of theElements; and then activating the supported metal species with asolution of an organo-metallic compound, a metallic constituent of whichis selected from Groups I, II and III of the Periodic Chart of theElements. The transition or Group VIII metal salt can be dissolved in anaqueous or nonaqueous medium to form the solution, depending on thespecific nature and character of the salt. Preferably, a water-solubleform of salt is used, and in impregnation of the support, subsequentactivation steps include: heat-treating the impregnated supportsufficient to form a complex of a species of the metal at the surface ofthe support and to remove liquid and adsorbed oxygen; activating thesupported metal complex by contacting same with a liquid solubleorganometallic compound, a metallic constituent of which is selectedfrom Groups I, II and III of the Periodic Chart of the Elements, andtreating the activated supported metal complex to eliminate volatilematter.

A highly tenacious chemical bonding can be formed between the surface ofcertain types of supports and transition or Group VIII metals,particularly iron, cobalt and nickel, of the Periodic Chart of theElements, when the latter are applied to the supports as solutions ofthe desired metal, and heat treated. The supported species, or productformed by the heat treatment, is further chemically altered andactivated by treatment with liquid soluble organometallic compounds,wherein the metal constituent of the compound is selected from Groups I,II and III of the Periodic Chart of the Elements.

Various solvents are suitable for dissolving metal salts,

including water which is particularly suitable for application of thetransition or Group VIII metal salt to the support. In the sequence ofprocess steps, in any event, a support is first impregnated with asolvent-soluble or water-soluble species of a transition or Group VIIImetal salt, preferably iron, cobalt, and nickel, by contact or immersionof the support in an organic or aqueous solution of a salt of thedesired metal. Suitably, the support is impregnated with from about 1 toabout 20 percent metal, and preferably from about 2 to about 10 percentmetal, based on the total weight of the deposited metal and support.

The use of water to effect the chemical bonding is particularlyimportant in the impregnation of the supports with the water-solublesalts of the desired Group VIII metal. Even iron has produced anexceptionally active catalyst when applied to the support in the form ofsalts dissolved in aqueous solution. Exemplary of water-soluble saltsuseful for application of the desired metals are halides, e.g., ferricchloride, ferrous chloride, cobaltous chloride, nickel chloride, nickelbromide, nickel fluoride, sulfates, e.g., ferric sulfate, ferrousammonium sulfate, nickel sulfate, cobaltous sulfate, nitrates, e.g.,cobaltous nitrate, nickel nitrate, ferric nitrate, water-solublecarboxylic acid salts, e.g., cobaltous acetate, nickel acetate, ferricor ferrous acetates, formates, propionates, and water-soluble phosphatesand the like. Exemplary of salts useful for application by solution inorganic solvents, e.g., petroleum naphthas, alcohols, ethers, ketonesand the like are the acetyl acetonates, carbonates, halides, chelates,and various heterocyclic compounds of iron, cobalt and nickel.

Where the support, in powder or granular form, is impregnated with anaqueous salt solution it is next treated by establishingtime-temperature relationships suitable to produce a chemical change onthe surface of the support and to remove water and adsorbed oxygen.Suitably, the impregnated support can be heated in air, in inert atmosphere or in vacuum, e.g., 20 to 29 inches of mercury, at from about 300"to about 1,200 E, or preferably from about 400 to about 800 F., forperiods ranging from about 0.5 to about 4 hours, or preferably fromabout 1 to about 2 hours. On the other hand, the reaction between thesalt and support can be accomplished by the elevated temperature whilemoisture is stripped from the support with nitrogen, or othernonreactive gas. If desirable, the impregnation and heat-treating stepscan be conducted in multiple stages. For example, the support can beimpregnated and thence dried, or partially dried, at low temperature.The support can thence be reimpregnated and again dried, or partiallydried. The heat treatment per se can also be conducted in multiplestages, if desired. The impregnated support, to facilitate handling, canthus be subjected to a first rather mild heat treatment to dry thesupport and thence, in a second step, to a more severe treatment toproduce the desired chemical change at the surface. In the formation ofsuch catalysts, supported catalysts such as supplied by commercialcatalyst manufacturers, e.g., iron, cobalt or nickel, alone or incombination with other metals such as molybdenum, tungsten or the like,are also amenable to such treatments to transform them into highlyactive catalysts.

Suitable supports are the oxides of Groups II, III, IV, V and VI-B ofthe Periodic Chart of the Elements, through the oxides of Groups II,III-A and IV-B are preferred. The Group III-A metal oxides, particularlyboria and alumlna, are especially preferred. Alumina supports, in fact,are quite outstanding from a cost-effectiveness standpoint and arereadily available. Silica-free alumina has been found especiallysuitable though silica alumina combinatrons of types used for crackingcatalysts are also highly active. Group II metal oxides, such as zincoxide, magnes1u m oxide, calcium oxide, strontium oxide and barium oxideand also the Group IV metal oxides, e.g., titanium oxide and zirconiumoxide, Group V metal oxides, e.g., vanadium oxide, and activated carbonand coke are effective. Certain natural clays, diatomaceous earths,e.g., kieselgnhr, and other supports are also useful.

The impregnated support is activated by treatment with anorgano-metallic compound, suitably a hydrocarbon solution of anorganometallic compound, a metallic constituent of which is selectedfrom Group I, II and III, or more preferably from Group I-A, II-B, andIII-A of atomic number ranging from 3 to 30, of the Periodic Chart ofthe Elements. Suitably, compounds include those having the formula:M(R,,)X wherein M is a Group I, II, or III, and preferably a Group I-A,II-B or III-A, metal having an atomic number of from 3 to 30; R ishydrogen or a monovalent organo or hydrocarbon radical, preferablyethyl, propyl, isopropyl, butyl, isobutyl, cyclopentyl, cyclohexyl,phenyl, naphthyl, and benzyl; X is selected from the group consisting ofhalogen, R, where R, is a hydrocarbon radical as previously describedfor R, and R and n is an integer ranging from 1 to 2. The R (and Rgroups can be the same or different, substituted or unsubstituted,saturated or unsaturated, and can be alkyl, aryl, alkaryl, aralkyl, orcycloalkyl. Such groups include, for example, methyl, ethyl, n-propyl,isopropyl, isobutyl, sec-butyl, tert-butyl, n-amyl, isoamyl, heptyl,n-octyl, n-dodecyl, and the like; 2-butenyl, 2- methyl-2-butenyl and thelike; cyclopentyl-methyl, cyclohexylethyl, cyclohexylpropyl and thelike; Z-phenyethyl, 2- phenylpropyl, Z-nap-hthylethyl, methylnaphthylethyl and the like; cyclopentyl, cycohexyl, 2,2,1-bicycloheptyland the like; methylcyclohexyl, dimethylcyclohexyl, -cyclopentadienyl,and the like; phenylcyclopentyl, and the like; phenyl, tolyl, xylyl,ethylphenyl, xenyl, naphthyl, cyclohexyphenyl and the like. In general,an R group can contain up to about 20 carbon atoms. M is selected fromsuch metals as lithium, magnesium, calcium, strontium, zinc, cadmium,boron and aluminum.

Preferred activating agents are the AlR3 or tri-alkyl substitutedproducts of aluminum, particularly those containing alkyl groups havingfrom one to about 12 carbon atoms, and more particularly thosecontaining from one to about four carbon atoms, especially linear alkylgroups. Exemplary of such compounds, which contain up to about 36 carbonatoms in the molecule, are trimethyl aluminum, triethyl aluminum,tri-n-butyl aluminum, trin-hexyl aluminum, tridodecyl aluminum and thelike.

The activation can be carried out with pure or diluted metal alkylcompounds in liquid or in the vapor phase. Hydrocarbon diluents of theparafiinic, cycloparafiinic or aromatic types are entirely suitable andthe metal alkyl compound may be present in concentrations of 5 percentto 50 percent in the diluent. A solution of about 20 percent aluminumtriethyl in a parafiinic diluent is a preferred activation system. Theactivation reaction is quite exothermic and it may be desirable toremove the heat of activation. The temperature during the activationstep is maintained in the range of from about -'60 to about 500 F.,preferably from about 100 to about 200 F. The molar ratio of complexingagent (in terms of, e.g., the aluminum to the transition or Group VIIImetal) ranges from about 1:1 to about 15:1. Considerable gas liberationoccurs during activation and these gases are normally vented from thesystem. The activation is allowed to proceed until reaction is no longerobserved, generally 0.5 hour to 2 hours in contact with at least someexcess of metal alkyl compound.

After the activation step, the excess liquid can be drained from thecatalyst, if desired. In any event, it is necessary to remove theunreacted organo-metallic activating agent, unbound byproducts andvolatiles from the catalyst. This can be done by any suitable methodsuch as by washing, drying or the like, but preferably the activatedcatalyst is subjected to heat-treatment at temperatures sufficient tothoroughly dry and condition the catalyst. A heat treatment is necessaryfor activation. Preferably, the heat treatment is conducted in anon-reactive or hydrogen atmosphere at temperatures ranging from about250 to about 800 F., and more preferably from about 200 to about 500 F.,for periods ranging up to 24 hours, and preferably from about 0.5 toabout 4 hours, or more preferably from about 1 to about 2 hours.Complete or partial vacuum may also be used to aid in removal of excesssolvent and organo-metallic alkyl compounds.

The exact nature of the complex formed in the activation step is notknown, but it is believed that this step produces a metal-to-metal bondbetween the metal species of the salt and the metal species of which thesupport is formed. For example, in activation of a nickel saltimpregnated upon an alumina support it is believed that the nickelbecomes bonded to active sites on the support, probably to aluminum. Thetransition or Group VIII metal species, therefore, becomes highlydispersed in atomic form rather than in bulk crystallite form as inconventional catalysts, producing a highly active and stablehydrogenation catalyst.

The following examples demonstrate the more salient features and providea better understanding of the invention. In the examples immediatelyfollowing, a commercial type nickel catalyst is employed inhydrogenation of the feedstock, or white oil base stock, because of itsknown high activity and these results are compared pari passu with theprocess of this invention under similar conditions, with a similarcatalyst except that the catalyst is activated with a preferred speciesof organometallic.

The examples immediately following first illustrate a method ofpreparing complexed transition or Group VIII metal catalysts.

EXAMPLE 1 Approximately 39 g. of nickel acetylacetonate is dissolved in350 cc. of hot toluene. 75 g. of 12-20 mesh activated alumina is addedto the solution. The solvent is evaporated by heating. 86.5 cc. oftriisobutyl aluminum in 260 cc. of n-heptane is added to the nickelimpregnated support. The aluminum-to-nickel atomic ratio is 2.5: l. Thenickel complex is heated in a hydrogen stream at 600 F. to remove thesolvent and yield a catalyst containing about 10 weight percent nickel.

EXAMPLE 2 A conventional nickel catalyst is prepared by reducing acommercial nickel catalyst containing 44 percent as the hydrate,distended on kieselguhr. Reduction is accomplished by heating cc. of thecatalyst in a stream of hydrogen at 600 F., 800 p.s.i.g. and 2.0s.c.f./hr. for 20 hours.

The catalysts of Examples 1 and 2 are tested comparatively in the samereactor. The feedstocks, or white oil base stocks, are nonsolventextracted naphthenic lubricating oil distillates previouslyhydrodesulfurized at 700 F. and 1500 p.s.i.g. in the presence of cobaltmolybdate catalyst to reduce the sulfur content of the oil to less than2 parts per million. The conditions for the hydrofinishing treatment are500 F., 2000 p.s.i.g., 0.25 v./hr./ v. and 3,000 s.c.f./bbl. hydrogen.

Four tests, quite rigorous in their nature, are used to assess theextent of hydrogenation of the white oil feedstock. These are:

(a) Saybolt color;

(b) percent of aromatics, as determined by liquid chromatography onsilica gel adsorbent;

(c) UV absorption coefiicient of the oil at 270-278 mp expressed as LogIo/I concentration X path length see Haenne et al., Journal of theO.A.O.C., vol. 43,

No. 1, pp. 92-95 (1960), on UV absorption as measured by ASTM D-2008 andASTM D-2269; and

7 (d) the test for carbonizable substances, AST M D- 65,

also known as the Hot Acid Test.

The test results are shown in Table I which describe the successfulpreparation of technical grade white oils when using the process of thisinvention.

Table I thus shows the results obtained with the two catalysts for a lowvelocity feedstock (Feed A, having a 60.6-71.9 percent yield on crude)is prepared, and phenolextracted to produce a raflinate in 40-45 percentyield, based on the weight of the distillate. The rafiinate ishydrodesulfurized over a 5/25 cobalt molybdate catalyst at 1,500p.s.i.g., 700 F. and 0.25 v./v./hr. and then topped to 800 F., at 80percent yield, to provide a semirefiued oil.

TABLE II Catalyst Commercial Feed B Nickel complex reduced nickelTemperature, F 500 500 Pressure, p.s.i.g 2. 000 2, 000 Space velocity,LHSV 0. 25 0. 25 HiThroughput, s.c.f./bbl 3,000 3, 000 No. Passes 1 2 12 Inspections:

Viscosity at 100 F., SSU. 478 450 439 462 453 Color, Saybolt 16% TR +29+35 +24 +28 Aromatics, weight percent 28. 9 1. 6 Nil 11. 4 5.3 UVAbsorption 270-278 11141., 1.1g.

cm 1.045 C. 014 0. 0087 0. 502 0. 084 Carbonizable substances, ASTMD-565, Color N o Black Brown Black B lack Tag Robinson.

viscosity at 100 F. of 75 SSU). The rather insensitive test with silicagel chromatography shows that the products from hydrogenation with bothcatalysts contains esucts from hydrgenation with both catalysts containsessentially no aromatics. The more sensitive UV absorption and Hot AcidTests, which are necessary to reveal the very low aromatics content todetermine whether or not the products can meet the rigid high qualitystandards required of white oils, however, show that the nickel complexprovides a product which contains considerably smaller traces ofaromatics than the product obtained when using the conventional reducednickel catalyst. The difi'erence is profound, and quite significant forproducts intended for use as white oils.

Tag Robinson.

The same comparative test is carried out on a semirefined high viscositynaphthenic lubricating oil feed (Feed B) having a viscosity at 100 F. of478 SSU. The test results are shown in Table II.

All four tests demonstrate, as shown by reference to Table II, thesuperiority of the nickel complex catalyst in providing high puritytechnical grade white oils. Thus the process of the invention providesan effective means for producing specification grade white oils.

The following example further demonstrates that even products meetingspecifications for pharmaceutical-grade white oils can be made pursuantto the practice of this invention.

EXAMPLE 3 In Table III, data are again given comparing the process ofthis invention using a complex nickel catalyst vis-a-vis a commerciallyavailable nickel catalyst. The example also shows a preferred processingsequence of steps involving solvent extraction to produce a higher gradeof semirefined feed.

A Tia Juana heavy grade distillate (850-1,050" F.;

The semirefined oil is then hydrogenated at 2,000 p.s.i.g., 500 F., 0.25v./v./hr., and 2,000 s.c.f./bbl. first over the commercial catalyst asdefined in Example 2, and then over the alkyl activated catalyst definedin Example 1. The results are tabulated in Table III.

1 Did not pass.

Overall yield, based on the initial distillate, is 31 percent. It isthus seen by comparison of the above data that the process utilizing thecatalyst of this invention readily produces finished pharmaceuticalgrade white oil, in good yield, Whereas the process employing thecommercial nickel catalyst cannot, even though the same optimumoperating conditions are employed.

EXAMPLES 4-6 (A) Tia Juana light grade oil, 675 -800 F. distillate,45.1-52.4 percent, based on the weight of crude, is phenolextracted andsubjected to hydrodesulfurization as in the foregoing example, and thentopped to 600 F., at percent yield. This feedstock, or white oil basestock, is then hydrogenated with aluminum alkyl reduced metal catalystsat 2,000 p.s.i.g., 500 F. and 0.36 LHSV prepared as follows:

(A) One hundred grams of aqueous solution is prepared by dissolving 34grams FeCl -6H 0 in 66 grams of water. One hundred grams F-l alumina(8-14 mesh) is added to the solution and allowed to stand withoccasional mixing for about 30 minutes. A small quantity of liquid ispoured off and the catalyst freed of excess liquid by placing onabsorbent paper towels. The catalyst is dried for 3 hours in a vacuumoven at 475550 F. The recovered catalyst weighs 107.4 grams, andanalyzes 5.3 percent iron (calculated as Fe).

A heated quartz reaction tube is charged with 25.7 grams of the abovecatalyst and a preheat area above the catalyst bed is filled withstainless steel distillation packing. The catalyst is heated in a streamof dry nitrogen at a temperature of 500-550 F. for one hour and is thencooled in nitrogen to room temperature. The reactor is flooded from thebottom with a 20 percent solution of aluminum triethyl. Considerable gasis evolved and the maximum temperature reached is 200 F. After 1.33hours, the solution is withdrawn. A rapid flow of nitrogen is introducedand the temperature is increased to 350 F. Stripping is continued forabout 30 minutes.

(B) A commercial cobalt molybdena-on-alumina catalyst (Nalco 471A)containing about 3.5 percent C and 12 percent M00 and in the form of-inch extruded rods calcined at 1,200 F. for 12 hours and then charged(36.7 grams) to the quartz reaction tube is heated in a flow of drynitrogen. After cooling in dry nitrogen, the catalyst bed is floodedwith 20 percent aluminum triethyl. Maximum temperature reached is 160 F.After 40 minutes, the solution is withdrawn and the catalyst brought to600 F. in a stream of dry hydrogen. Substantially all volatile materialis removed in 15 minutes at 500 F.

(C) One hundred grams of F-l alumina is slurried with 200 ml. water withmechanical agitation. Over a period of 5 minutes, 20 ml. platinumchloride HCl solution (0.56 gm. Pt) is added and agitation continued for30 minutes. Liquid is decanted off and the catalyst is dried in a vacuumoven at 170 F. The catalyst analyzes 0.13 weight percent platinum.

The quartz tube is charged with 48.2 gms. of the above catalyst and thecatalyst is heated in a stream of dry nitrogen at 600 F. for 1 hour.After cooling to room temperature, the catalyst is treated with 20percent AlEt (heptane) solution for a period of 90 minutes during whichthe maximum temperature noted is 215 F.

After draining off the liquid, the catalyst is treated in a flow of dryhydrogen at 400 F. for 1 hour.

In each instance it is found that a suitable technical grade white oilis prepared.

What is claimed is:

1. A process for producing a white oil comprising contacting a lowsulfur content white oil base stock boiling within a range of from about400 to about 1025 F. and having a viscosity ranging from about 35 toabout 2500 SSU at 100 F. at hydrogenation conditions with hydrogen and acatalyst comprising a complex of a metal selected from the groupconsisting of iron, cobalt and nickel composited with a support selectedfrom the group consisting of alumina, silica-alumina and boria, saidcatalyst having been prepared by reacting a composite of a salt of thesaid metal and said support with an aluminum compound having the generalformula AlR in which R is an alkyl, aryl, alkaryl, aralkyl, orcycloalkyl radical and then heating the reacted composite in anon-reactive or hydrogen atmosphere to activate [the] said catalyst.

2. The process of claim 1 wherein the sulfur content of the white oilbase stock is less than about 5 ppm.

3. The process of claim 1 wherein the boiling range of the white oilbase stock ranges from about 650 to about 1025 F.

4. The process of claim 1 wherein the catalyst composite comprises [of]nickel on alumina.

5. The process of claim 1 wherein the viscosity of the white oil basestock ranges from about 35 to 500 SSU at 100 F.

6. A process for producing white oil from a petroleum lubricating oilfraction containing contaminants including aromatic hydrocarbons, sulfurcompound and nitrogen compounds comprising the steps of (a) contactingsaid fraction at a temperature in the range of about 400 to 800 F. and apressure in the range of about 500 to 5000 p.s.i.g. with hydrogen and afirst catalyst comprising a support material and a hydrogenationcomponent selected from the group consisting of Group VI-B metals, GroupVIII metals and mixtures thereof;

(b) recovering a semi-refined fraction having a substantially reducedquantity of said contaminants; and

(c) contacting said semi-refined fraction at relatively mildhydrogenation conditions with hydrogen and a second catalyst comprisingcomplexed metal on alumina, said metal being selected from the groupconsisting of iron, cobalt and nickel, and said second catalyst havingbeen complexed by reacting said metal on alumina with an aluminumcompound having the general formula AlR in which R is an alkyl, aryl,alkaryl, aralkyl or cycloalkyl radical.

7. The process of claim 6 wherein the said second catalyst comprisescomplexed nickel on alumina, said catalyst having been prepared byreacting a nickel on alumina composite with the said aluminum compound.

8. A process for producing a white oil consisting essentially of thesteps of:

(a) extracting a naphthenic lubricating oil fraction with a solvent toremove aromatics;

(b) recovering a raflinate fraction comprising a 30 to 75 volume percentof said lubricating oil fraction;

(c) contacting said raffinate with hydrogen at a temperature in therange of 600 to 800 F. and a pressure in the range of 1000 to 10,000p.s.i.g. in the presence of a catalyst comprising a support material anda hydrogenation component selected from the group consisting of GroupVI-B metals, Group VIII metals and mixtures thereof;

(d) recovering a semi-refined white oil;

(e) distilling the semi-refined white oil to obtain a topped fractionhaving a viscosity in the range of 30 to 2500 SSU at F.;

(f) contacting said topped fraction with hydrogen at a temperature inthe range of 475 to 525 F. and a pressure in the range of 1000 to 10,000p.s.i.g., and with a catalyst composite comprising a supported complexmetal catalyst, said catalyst having been prepared by impregnating asupport selected from the group consisting of alumina, silica-aluminaand boria, with a salt of a metal selected from the group consisting ofiron, cobalt and nickel, heating said impregnated support [to form saidsupport complex metal catalyst], thereafter reacting said [supportedcatalyst] impregnated support with an aluminum compound having thegeneral formula AlR in which R is an alkyl, aryl, alkaryl, aralkyl orcycloalkyl radical, and then heating the reacted catalyst in anonreactive or hydrogen atmosphere to activate [the] said catalyst; and

(g) recovering a white oil which passes the Hot Acid Test.

9. The process of claim 8 wherein the solvent is phenol.

10. The process of claim 8 wherein the catalyst contacted by therafiinate in step (c) comprises a sulfided cobalt molybdate on alumina.

11. The process of claim 8 wherein the supported complex metal catalystis nickel on alumina.

12. The process of claim 8 wherein the topped semirefined white oil isone having a viscosity ranging from about 30 to about 500 SSU at 100 F.

13. A process for processing white oil comprising forming a white oilbase stock by [at] extracting an oil boiling in a range of from about400 to about 1025 F., and having a viscosity of about 35 to about 2500SSU at 100 F. with a solvent to produce a rafiinate of reduced aromaticcontent, said raffinate boiling within the range of from about 400 toabout 1025 F.,

hydrodesulfurizing the raflinate by contact with a hydrogenationcatalyst comprising a support material and a hydrogenation componentselected from the group consisting of Group VI-B metals, Group VIIImetals and mixtures thereof, at a temperature ranging from about 400 to800 F., a pressure ranging from about 1000 to 10,000 p.s.i.g., spacevelocities 1 1 ranging from about 0.1 to 10 v./hr./v., and at hydrogenrates of from about to 10,000 s.c.f./bbl., contacting said desulfurizedoil at hydrogenation conditions with hydrogen and a catalyst compositecomprising a support selected from the group consisting of alumina,silica-alumina and boria, and a metal selected from the group consistingof iron, cobalt and nickel, said catalyst composite having been preparedby reacting the said composite with an aluminum compound having thegeneral formula A1R in which R is an alkyl, aryl, alkaryl, aralkyl orcycloalkyl radical, and

recovering a colorless white oil containing essentially no aromaticcompounds.

14- The process of claim 1 wherein said catalyst, after reaction withsaid aluminum compound, is heated in a hydrogen atmosphere to activatesaid catalyst.

15. The process of claim I wherein said aluminum compound is a trialkylsubstituted aluminum.

16. The process of claim 1 wherein said catalyst, after reaction withsaid aluminum compound, is heated in a hydrogen atmosphere at atemperature varying from 250' to 800 F. to activate said catalyst.

17. The process of claim 4 wherein said catalyst composite is reactedwith triethyl aluminum and thereafter heated in a hydrogen atmosphere ata temperature in the range of from about 250 to 800 F.

18. The process of claim 6 wherein said second catalyst, after havingbeen complexed by reaction with said aluminum compound, is heated in ahydrogen atmosphere to activate said catalyst.

19. The process of claim 6 wherein R is an alkyl radical having from 1to 12 carbon atoms.

20. The process of claim 19 wherein said second catalyst, aftercomplexing by reaction with said aluminum compound, is heated in ahydrogen atmosphere at a temperature varying from about 250 to 800 F.

21. The process of claim 7 wherein R is an alkyl radical having from 1to 12 carbon atoms.

22. The process of claim 7 wherein said aluminum compound is triethylaluminum and said second catalyst, after complexing by reaction withsaid aluminum compound, is heated in a hydrogen atmosphere at atemperature varying from 250 no 800 F.

23. The process of claim 8 wherein said supported catalyst, afterreaction with said aluminum compound, is heated in a hydrogen atmosphereto activate said catalyst.

24. The process of claim 8 wherein R is an alkyl radical having from Ito 12 carbon atoms.

25. The process of claim 24 wherein said supported complex metalcatalyst, after reaction with said aluminum compound, is heated in ahydrogen atmosphere at a temperature varying from about 250 to 800 F.

26. The process of claim I] wherein said impregnated support is reactedwith triethyl aluminum and thereafter the reacted catalyst is heated ina hydrogen atmosphere at a temperature varying from 250 to 800 F.

27. The process of claim 13 wherein the catalyst composite, afterreaction with said aluminum compound, is heated in a hydrogen atmosphereto activate said catalyst.

28. The process of claim 13 wherein R is an alkyl radical having from Ito 12 carbon atoms.

29. The process of claim 28 wherein said catalyst composite, afterreaction with said aluminum compound, is heated in a hydrogen atmosphereat a temperature varying from 250 to 800 F. to activate said catalyst.

30. The process of claim 6 wherein said first catalyst comprises asulfided nickel molybdate on alumina.

31. The process of claim 7 wherein said first catalyst comprises asulfided nickel molybdate on alumina.

32. The process of claim 8 wherein the catalyst contacted with saidraflinate in step (c) comprises a sulfided nickel molybdate on alumina.

33. The process of claim I] wherein the catalyst contacted with saidrafiinate in step (c) comprises a sulfided nickel molybdate on alumina.

34. The process of claim 13 wherein the catalyst employed in thehydrodesulfurization of the rafi'inate comprises a sulfided nickelmolybdate on alumina.

35. The process of claim 29 wherein the catalyst employed in thehydrodesulfurization of the rafiinate comprises a sulfided nickelmolybdate on alumina.

References Cited The following references, cited by the Examiner, are ofrecord in the patented file of this patent or the original patent.

UNITED STATES PATENTS 2,756,183 7/1956 Knox, Jr. 208-217 2,946,7437/1960 Moy et al. 208217 3,340,181 9/1967 Diringer et a1. 208-2113,392,112 7/1968 Bercik et al. 208-143 3,412,174 10/1968 Kroll 208-1433,414,506 12/ 1968 Van Lookeren Campagne 208264 3,705,093 12/1972Ashcraft, Jr. 208-89 3,723,296 3/1973 Hahn 208-89 3,728,250 4/1973 Hasset a1 208-89 DELBERT E. GANTZ, Primary Examiner G. J. CRASANAKIS,Assistant Examiner U.S. Cl. X.R. 208-210

